1. Field of the Invention
The present invention relates to a thin film magnetic head often employed in a magnetic recording medium drive such as a magnetic disk drive and a magnetic tape drive, and to a method of making the same. In particular, the invention relates to a thin film magnetic head comprising a lower magnetic pole layer extending rearward from the front end exposed at a medium-opposed surface, an upper magnetic pole opposed to the lower magnetic pole layer, and a lower auxiliary magnetic pole protruding toward the upper magnetic pole from the upper surface of the lower magnetic pole layer at the front end of the lower magnetic pole layer, and to a method of making the same.
2. Description of the Prior Art
Japanese Patent Application Publication 11-353614 discloses, for example, a lower auxiliary magnetic pole standing from the front end of a lower magnetic pole layer toward an upper magnetic pole so as to define a so-called gap depth of the thin film magnetic head. The lower auxiliary magnetic pole greatly contributes to establishment of a smaller gap depth irrespective of the extent of the upper magnetic pole opposed to the lower auxiliary magnetic pole. If the gap depth can be set smaller in this manner, the magnetic flux is allowed to be exchanged between the upper and lower magnetic poles so as to efficiently leak out of the medium-opposed surface of a head slider, for example. A stronger magnetic field for recordation can be realized in an efficient manner.
A non-magnetic material piece may be embedded in the lower magnetic pole layer. The non-magnetic material piece is employed to define the rear end of the lower auxiliary magnetic pole within the lower magnetic pole layer. A depression is formed on the upper surface of the lower magnetic pole layer prior to the embedment of the non-magnetic material piece. A plating process is utilized to form the depression. A magnetic material is allowed to deposit on the upper surface of the lower magnetic pole layer around a photoresist film patterning the shape of the depression in the plating process. After removal of the photoresist film, the depression is filled up with a non-magnetic material. However, when the plating process is to be employed to form the lower auxiliary magnetic pole, the lower auxiliary magnetic pole should suffer from less choice of the magnetic material.